Luke Bryan gave a nurse who's working the front lines of the coronavirus pandemic the surprise of a lifetime during a recent appearance on Good Morning America.

Cassidy Gubin works at Baptist Memorial Hospital in Memphis, Tenn., where she's been putting in 12-hour shifts caring for patients who've tested positive for coronavirus (COVID-19).

She gave an interview to TJ Holmes as part of his Tell TJ segment on the show, not knowing the surprise that lay in store. She told Holmes that she likes to go on long walks to relax away the stress of the job, and she likes to listen to music. Gubin named Bryan as an artist she particularly enjoys, saying, "His songs always just make me smile."

She named "Rain Is a Good Thing" as a favorite, and Bryan suddenly popped up in a new chat window and began singing the song, surprising the stunned nurse, who exclaimed, "Oh my gosh! Is this for real?"

"Thank you for everything you are doing on the frontline, you're inspiring people like us," Bryan tells Gubin in the video below. "We're told to sit home, and you're told to go straight into the hospital where actively sick patients are, so you are certainly a hero to me."

"You have no idea how much that means to me, and thank you so much for your music because it's all I listen to, it always makes me smile," Gubin tells the "One Margarita" singer.

"Oh my gosh, that was the coolest thing I've ever done," she gushes after his unexpected appearance on the call.

Bryan has been passing the time during the coronavirus quarantine with his family in Florida, where he's given a few live performances remotely and also participated in the last part of Season 18 of American Idol from home.

Blake Shelton also surprised two women working the front lines of the pandemic in a recent appearance on the Today Show, offering up a song for a mother and daughter who are both nurses in Louisiana on May 7.